A trick-the-eye illusionism represents a mysterious three-dimensional world not possible in reality on a two-dimensional plane, cleverly utilizing the characteristics of parallel projection transformation. For example, Escher's “Ascending and Descending” is an illusionism which represents mysterious stairs, where going around them once returns to the original position, endlessly ascending or descending by depicting staircases at different levels in actuality as if they are interconnected.
One of the inventors has conceived a completely new game utilizing the trick of the above-mentioned illusionism and has disclosed it at the following URL site.    [Non-patent Document 1] Jun Fujiki, “OLE Coordinate System”, [online], Oct. 6, 2006; Jun Fujiki, [Searched on Feb. 15, 2008], The internet <URL:http://tserve01.aid.design.kyushu-u.ac.jp/˜fujiki/ole_coordinate_system/index.html>